1. Field of the Invention
The present invention relates to a waterproof electronic equipment unit suitable for installing directly in, for example, an automobile transmission gear box, and in particular, relates to a waterproof electronic equipment unit improved so as to be able to effectively utilize a given installation environment.
2. Description of the Related Art
Generally, there are two types of waterproof electronic equipment unit wherein a circuit substrate is hermetically housed inside a frame configured of a base and cover, circuit components including a heat generating component, and an external wiring connector housing of which one portion is exposed from the frame, are mounted on the circuit substrate, and a waterproof sealing material is applied to joining surfaces of the base, cover, and connector housing, the two types being a type wherein the connector housing, which forms a high component, is disposed between the circuit substrate and cover, and a type wherein the connector housing is disposed between the circuit substrate and base.
The base in this case is one portion of the frame on a side having mounting legs for disposing and fixing the electronic equipment unit to a mounted surface, and the frame is configured by the cover being, for example, fixed by screwing to the base.
Also, air inside the frame is released to the atmosphere by providing a water-repellent filter on an inner surface of the cover or base, so as to prevent deformation of the frame structure or damage to the hermetic sealing structure that is caused by a difference in atmospheric pressures inside and outside the frame due to a rise in the temperature of the heat generating component inside the frame.
The water-repellent filter is configured of a flat porous material including a multiple of minute holes that prevent water droplets from flowing into and passing through the interior of the frame and allow air to pass freely through, but the installation structure is devised so that the porous material is not contaminated by direct contact with water.
For example, according to FIG. 3 of Patent Document 1 “Electronic Control Device Substrate Housing Frame”, a circuit substrate 40 on which is mounted a connector housing 41 is hermetically housed inside a substrate housing frame 10 configured of a base 30 and cover 20, mounting legs 32 are provided on the base 30 and disposed on and fixed to an unshown mounted surface, and the cover 20 is integrated with the base 30 by bent pieces provided at four corners being bent.
In Patent Document 1, the connector housing 41 is disposed between the circuit substrate 40 and cover 20, size is reduced by a high flat portion 22 and low flat portion 21 being provided on the cover 20, and heat generated by a heat generating component 43a is transferred to a heat transfer base portion of the base 30 by a heat transfer mechanism 12.
Also, according to FIGS. 1 and 2 of Patent Document 2 “Frame, and Method of Assembling the Frame”, a circuit substrate 40A on which are mounted connector housings 24Aa and 24Ab is hermetically housed inside a substrate housing frame 10A configured of a case 20A, corresponding herein to a base, and cover 30A, mounting holes 21a to 21d are provided in mounting legs of the base (case) 20A and the mounting legs disposed on and fixed to an unshown mounted surface, and the cover 30A and base (case) 20A are integrated using four corner screws 31a to 31d and screw holes 22a to 22d of the base (case) 20A.
In Patent Document 2, the connector housings 24Aa and 24Ab are disposed between the circuit substrate 40A and base (case) 20A, and straight type connection pins 25a and 25b are force fitted into body portions of the connector housings 24Aa and 24Ab and connected by soldering to the circuit substrate 40A.
Also, heat generated by a heat generating component 42 is transferred to a heat transfer base portion of the base (case) 20A via a heat transfer conductor 43.    Patent Document 1: JP-A-2013-004611 (FIGS. 1 and 3, Abstract)    Patent Document 2: JP-A-2014-060307 (FIGS. 1, 2, and 4, Abstract)